ALLERGEN-SPECIFIC HUMAN T-CELL CLONES PRODUCE INTERLEUKIN-5 UPON STIMULATION WITH THE TH1 CYTOKINE INTERLEUKIN-2

CD4+ T cell clones specific for DerfII (a major allergen of the house dust mite) were established from peripheral blood mononuclear cells of atopic patients. All of the T cell clones were classified as having t he ThO phenotype, since they produced both interleukin (IL)-2 and IL-4 upon stimulation. Some of the clones produced IL-5 upon antigenic sti mulation. Human recombinant IL-2 induced these T cell clones to expres s IL-5 mRNA and produce IL-5 protein in a dose-dependent manner. IL-2 did not induce IL-4 production, indicating a discrete signal requireme nt for IL-4 versus IL-5 production by T cells. Moreover, IL-5 producti on induced by immobilized anti-CD3 monoclonal antibody was completely suppressed by the addition of anti-IL-2 monoclonal antibody, suggestin g that IL-5 production, designated as a Th2-type immune response, is d ependent on IL-2, a Th1 cytokine. IL-2 produced at the site of allergi c inflammation may contribute to IL-5 production by T cells in vivo.